骨盆（Pelvic）由Pubis, Ischium, ilium , sacrum和Coccyx所組成，其底部稱為骨盆底(Pelvic Floor)。腹骨盆腔內的尿道、陰道和直腸等器官，穿過骨盆底與外交通，骨盆底部需承受重力與腹壓，維持排泄與生產功能。在骨盆腔內的Endopelvic Fasciae，且有Felt-like meshwork的結構，對骨盆內器官具有懸吊的功能。包括Cardinal ligaments和Uterosacral ligaments支持Uterus和Upper vagina，Urethropelvic ligament和periurethral fascia支持Bladder和Proximal urethra，以及陰道後壁和直腸間的Rectovaginal septum。 Pubococcygeus, Iliococcygeus與Coccygeus muscle形成骨盆底（Pelvic diaphragm）;前兩者與Puborectails muscle構成Levator ani muscle，這些肌群是Kegel’s exercises所強化的主要肌肉。Pubococcygeus和Iliococcygeus muscle由外側向內延伸形成Levator plate（Anococcygeal raphe），在人體站立腹內壓升高時提供子宮，陰道後與直腸的緩衝平台，防止脫垂與失禁。骨盆的開口有Urogenital diaphragm（Perineal membrane）所覆蓋，以穩定生殖泌尿道的出口構造。其下方有Ischiocavernosus muscles, Bulbocavernosus muscle和Superficial transverseperineal muscles等External genital muscles，其神經由Pudendal nerves分枝所支配。而Superficial transverse perineal muscles 和 External anal sphincter收縮時，可提高和支撐 Perineal body。但女性懷孕、生產與停經等階段，都有可能對骨盆腔底結構造成損傷，而使內部的器官發生脫垂和失禁等功能，其臨床上所表現出來的症狀，可以”Boat-in-dry”的model來說明。

The levator ani muscles and urogenital diaphragm (perineal membrane) comprise the main part of the pelvic floor. Together with the bulbocavernous, ischiocavernous, and superficial transverse perineal muscles, the perineal body, external anal sphincter, and the pelvic floor seal off the lower aspect of the pelvic cavity. The pelvic floor provides normal supportive mechanism to overcome the stress of gravity, and this increase in abdominal pressure in the erect biped posture. All forms of uterovatinal prolapse involve downward protrusion of the vaginal wall through the pelvic floor. Nevertheless, there are 3 mechanisms, which help maintain a normal position of the vagina, i.e, constriction, suspension, and a flap valve closure which can prevent downward organ prolapse. Unfortunately, trauma to the pelvic floor during childbirth and chronic stress of increasing intra-abdominal pressure, which cause breakdown of these supporting mechanisms will lead to subsequent pelvic relaxation. In order to explore the nature of genital prolapse and understand the role of the pelvic floor, it is necessary to appreciate the anatomy of the pelvic region